Soften mushrooms according to package directions using 1 1/2 cups water. Drain, reserving liquid. Coarsely chop mushrooms; reserve 1/2 cup. Season ribs with salt and pepper. In ovenproof Dutch oven, heat oil over medium heat. Working in batches, cook ribs until well browned on all sides (about 10 minutes per batch). Transfer with tongs to bowl. Pour off all but 2 tablespoons fat from Dutch oven. Add shallots, carrots, celery, prosciutto and garlic; saute until vegetables begin to soften (5 minutes). Stir in mushrooms, mushroom liquid, wine, broth, rosemary and bay leaf. Add ribs; bring to a boil. Place in oven. Braise, covered, in a preheated 350 F oven until ribs are tender (1 1/2-2 hours).